package com.hdu.hot100.doublePointer;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

public class lc15 {
    class Solution {
        public List<List<Integer>> threeSum(int[] nums) {
            Arrays.sort(nums);
            List<List<Integer>> ans = new ArrayList<>();
            for (int i = 0; i < nums.length; i++)
            {
                if (i > 0 && nums[i] == nums[i - 1]) continue;
                int left = i + 1;
                int right = nums.length - 1;
                while (left < right)
                {
                    int sum = nums[i] + nums[left] + nums[right];
                    if (sum == 0)
                    {
                        ans.add(Arrays.asList(nums[i], nums[left], nums[right]));
                        while (left < right && nums[left] == nums[left + 1]) left++;
                        while (left < right && nums[right] == nums[right - 1])right--;
                        left++;
                        right--;
                    }
                    else if (sum < 0) left++;
                    else right--;
                }
            }
            return ans;
        }
    }
}
